Lamp filament support and connection



Sept. 21, 1948. I l. H. VAN HO RN 254493579 LAMP FILAMENT S UPIQR'I; AND CONNECTION Filed Nov. 50, 1944 I N VEN' 70 Patented Sept 21, 1948- LAMP FILAMENT SUPPORT AND CONNECTION Irving H. Van Horn, East Cleveland, Ohio, assign-' or to General Electric Company, a corporation of New York Application November 30. 1944, Serial No. 585,825 Claims. (Cl. 176-39) This invention relates to electric lamps and filament mounts, and especially to supports and current connections for filaments. The invention is here illustrated and explained as embodied in end supports which also serve as current supply connections, thoughit might also be applied to supports that sustain an intermediate portion of a filament, or do not carry current, or both. The filament mount here shown is of a concentrated coil type; but the invention is not limited to any particular type of mount. Various features and advantages of the invention will become apparent from the description of species and forms of embodiment, and from the drawings.

In the drawings,

Fig. l is a side view of a biplane coiled filament mount, for an incandescent lamp, that convenlently embodies the invention, portions of the lamp bulb being also shown.

Fig. 2 is a partly sectional view, on a largerscale, illustrating the attachment and electrical connection of a current lead and support to a filament; and I Fig. 3 is a similar view illustrating a different form of construction.

The mount here illustrated is that of a projection lamp of moderately high wattage, comprising a filament. of tungsten wire coiled in a number of upright sections I that are interconnected by intermediate uncoiled U-portions or bights 2. The coils I may be staggered so as to lie alternately in two parallel planes. The supporting structure of the mount comprises leadwlres 3, 3 sealed through the pressed seal 6 of an ordinary stem flare portion 5 of the lamp envelope. These leads 3, 3 are shown as offset outward at 6, B, and then bent inward at l, 1 near their upper ends. Long upright side sections 8, 8 of the leads 3, 3 (opposite and above and below the filament coils I) may consist of refractory metal like molybdenum interposed between lengths of ordinary metal like nickel, butt-welded to the ends of the molybdenum. For engaging and holding the filament bights 2, there are upper and lower (molybdenum) wire hooks 9, ill whose ends are fused into the sides of upper and lower vitreous crossbars ll, 12. The upper bar II is supported by wires I3 fused into its lower side near its ends and welded to the inbent upper lead portions 1, l, and the lower bar 12 is supported by bent wires i4 fused into its upper side near its ends and welded to the lower lead portions 6. 6. Bent spacing wires I5 fused into the lower side of the upper bar ii between hooks land wires l3 may be pro-- vided for engaging the lamp bulb and bracing the mount transversely therein.

To hold the coiled and sections I of the filament taut or under. suitable tension, and to connect the current leads 3. 3 to these ends, supporting connections l6, it according to my invention are shown. In the form here illustrated, each of these comprises a spud like member I6 of suitable size wire provided with a helical screw thread and having one end screwed into and completely through a helically coiled filament end portion II, which may be connected to the adjacent coiled section I by an uncoiled length l8. The other end of the member i6 is shown welded to the portion I of the corresponding lead 3. The coil I1 is not only in screw mesh with the threads of the member I6, but in definite frictional engagement with them. To this end, the coil ll may be coiled to a size slightly smaller than that of the threads of member 18, so that the coil will elastically grip the member when the latter is screwed into the coil. When the member I6 is screwed completely through the coil I1, the frictional contact of the screw threads in the coil Il short-circuits all the coil turns, so that a definite length of filament exclusivepf the coils I l, I! is in circuit between the connectors i6, ii. The spuds IB, I8

may preferably be weldedto the lead portions 1, 1 after being screwed into the'filament coils l'l, H, which may conveniently be done before the filament is placed on the hooks 9, ill.

Asshown in Fig. 2, the screw thread on the member It consists of a coil of wire 19 tightly fitting around and irictionally gripping the mem-.

ber. Although this is not essential, the wire 19 is shown finer than the filament wire, as well as finer than the member IS. The wire l9 may either be wound on the member l8 under suitable molybdenum, including in the Fig. 1 type the winding I9 as well as the member l8. In both cases, the pitch of the screw threads of member l8 may be approximately the same as that of the coasting filament coil II. In manufacture, it is convenient and economical to screw thread long lengths of wire and cut them up into Fig. 3 type spuds it of suitable length; or to wind long lengths of unthreaded wire it with the wire l9,

heat-treat the same to set the coil II, and then cut the overwound wire up into proper spud lengths oi Fig. 2 type;

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric lamp comprising a mount including supporting structure and a coiled filament. and aspud tor tensioning coil convolutions of said filament attached to said supporting structure and provided with screw threads in screw mesh and frictional engagement with other coil convolutions of said filament, the said screw mesh trictional interengagement providing the sole electrical and mechanical connection of the spud to the filament.

2. In a filament mount. the combination with a support of a spud attached'at one end to said support and provided with screw threads on its other end, and a filament having a helically coiled portion in screw mesh and frictional engagement with the threads .on the said other end of said spud, the said screw mesh frictional interengagement of the said screw threads and helically coiled portion 01 the filament providing the sole electrical and mechanical connection of the spud to the filament.

8. In combination, a filament support comprising a mandrel member, a helical wire coil having convolutions fitted around and directly gripping said member, thus forming screw threads on said w 1,405.545

coil and helically coiled portion of the filament 35 providing the sole electrical and mechanical conmotion of the filament to the mandrel member.

4. In an electric incandescent lamp, the combination of a lead-in conductor, a spud secured at one end to said conductor and provided with screw threads on its other end, and a filament having a coiled end portion screwed tightly over the threaded end oi said spud. the screw mesh interengagement oi' the said screw threads and coiled end portion 01 the filament providing the sole electrical and mechanical connection or the spud to the filament.

5. In an electric incandescent lamp. the combination of a lead-in conductor. a spud secured IRVING H. VAN HORN. v

} REFERENCES CITED The following references are of record in the file of this patent:

UNITED STQTES PATENTS Number Name Date Heany Feb. 14, 1922 1,740,391 Campbell Dec. 17, 1929 2,134,574 Pinkie Oct. 25, 1938 2,140,977 Allen Dec. 20, 1938 2,404,992 Stone July 20, 1946 

